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Commit b5aeca54 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 uprobe/kprobe fixes from Ingo Molnar:
 "This contains two uprobes fixes, an uprobes comment update and a
  kprobes fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes/x86: Mark 2 bytes NOP as boostable
  uprobes/x86: Fix 2-byte opcode table
  uprobes/x86: Fix 1-byte opcode tables
  uprobes/x86: Add comment with insn opcodes, mnemonics and why we dont support them
parents 3f4d9925 b7e37567

arch/x86/kernel/kprobes/core.c

+1 −1
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ static volatile u32 twobyte_is_boostable[256 / 32] = { 
	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */

	/*      ----------------------------------------------          */

	W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */

	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */

	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */

	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */

	W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */

	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */

arch/x86/kernel/uprobes.c

+110 −43
Original line number Diff line number Diff line
@@ -66,27 +66,54 @@ 
 * Good-instruction tables for 32-bit apps.  This is non-const and volatile

 * to keep gcc from statically optimizing it out, as variable_test_bit makes

 * some versions of gcc to think only *(unsigned long*) is used.

 *

 * Opcodes we'll probably never support:

 * 6c-6f - ins,outs. SEGVs if used in userspace

 * e4-e7 - in,out imm. SEGVs if used in userspace

 * ec-ef - in,out acc. SEGVs if used in userspace

 * cc - int3. SIGTRAP if used in userspace

 * ce - into. Not used in userspace - no kernel support to make it useful. SEGVs

 *	(why we support bound (62) then? it's similar, and similarly unused...)

 * f1 - int1. SIGTRAP if used in userspace

 * f4 - hlt. SEGVs if used in userspace

 * fa - cli. SEGVs if used in userspace

 * fb - sti. SEGVs if used in userspace

 *

 * Opcodes which need some work to be supported:

 * 07,17,1f - pop es/ss/ds

 *	Normally not used in userspace, but would execute if used.

 *	Can cause GP or stack exception if tries to load wrong segment descriptor.

 *	We hesitate to run them under single step since kernel's handling

 *	of userspace single-stepping (TF flag) is fragile.

 *	We can easily refuse to support push es/cs/ss/ds (06/0e/16/1e)

 *	on the same grounds that they are never used.

 * cd - int N.

 *	Used by userspace for "int 80" syscall entry. (Other "int N"

 *	cause GP -> SEGV since their IDT gates don't allow calls from CPL 3).

 *	Not supported since kernel's handling of userspace single-stepping

 *	(TF flag) is fragile.

 * cf - iret. Normally not used in userspace. Doesn't SEGV unless arguments are bad

 */

#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)

static volatile u32 good_insns_32[256 / 32] = {

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

	/*      ----------------------------------------------         */

	W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 00 */

	W(0x00, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 00 */

	W(0x10, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) , /* 10 */

	W(0x20, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1) | /* 20 */

	W(0x30, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1) , /* 30 */

	W(0x20, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 20 */

	W(0x30, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 30 */

	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */

	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */

	W(0x60, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */

	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */

	W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 70 */

	W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */

	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */

	W(0xa0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* a0 */

	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* b0 */

	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* c0 */

	W(0xd0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xe0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* e0 */

	W(0xf0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */

	W(0xf0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */

	/*      ----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

};
@@ -94,27 +121,61 @@ static volatile u32 good_insns_32[256 / 32] = { 
#define good_insns_32	NULL

#endif



/* Good-instruction tables for 64-bit apps */

/* Good-instruction tables for 64-bit apps.

 *

 * Genuinely invalid opcodes:

 * 06,07 - formerly push/pop es

 * 0e - formerly push cs

 * 16,17 - formerly push/pop ss

 * 1e,1f - formerly push/pop ds

 * 27,2f,37,3f - formerly daa/das/aaa/aas

 * 60,61 - formerly pusha/popa

 * 62 - formerly bound. EVEX prefix for AVX512 (not yet supported)

 * 82 - formerly redundant encoding of Group1

 * 9a - formerly call seg:ofs

 * ce - formerly into

 * d4,d5 - formerly aam/aad

 * d6 - formerly undocumented salc

 * ea - formerly jmp seg:ofs

 *

 * Opcodes we'll probably never support:

 * 6c-6f - ins,outs. SEGVs if used in userspace

 * e4-e7 - in,out imm. SEGVs if used in userspace

 * ec-ef - in,out acc. SEGVs if used in userspace

 * cc - int3. SIGTRAP if used in userspace

 * f1 - int1. SIGTRAP if used in userspace

 * f4 - hlt. SEGVs if used in userspace

 * fa - cli. SEGVs if used in userspace

 * fb - sti. SEGVs if used in userspace

 *

 * Opcodes which need some work to be supported:

 * cd - int N.

 *	Used by userspace for "int 80" syscall entry. (Other "int N"

 *	cause GP -> SEGV since their IDT gates don't allow calls from CPL 3).

 *	Not supported since kernel's handling of userspace single-stepping

 *	(TF flag) is fragile.

 * cf - iret. Normally not used in userspace. Doesn't SEGV unless arguments are bad

 */

#if defined(CONFIG_X86_64)

static volatile u32 good_insns_64[256 / 32] = {

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

	/*      ----------------------------------------------         */

	W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 00 */

	W(0x00, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1) | /* 00 */

	W(0x10, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 10 */

	W(0x20, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) | /* 20 */

	W(0x30, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0) , /* 30 */

	W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */

	W(0x20, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) | /* 20 */

	W(0x30, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0) , /* 30 */

	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */

	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */

	W(0x60, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */

	W(0x60, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* 60 */

	W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 70 */

	W(0x80, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */

	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */

	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1) , /* 90 */

	W(0xa0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* a0 */

	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* b0 */

	W(0xc0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* c0 */

	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0) | /* c0 */

	W(0xd0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xe0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* e0 */

	W(0xf0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */

	W(0xe0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0) | /* e0 */

	W(0xf0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1)   /* f0 */

	/*      ----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

};
@@ -122,49 +183,55 @@ static volatile u32 good_insns_64[256 / 32] = { 
#define good_insns_64	NULL

#endif



/* Using this for both 64-bit and 32-bit apps */

/* Using this for both 64-bit and 32-bit apps.

 * Opcodes we don't support:

 * 0f 00 - SLDT/STR/LLDT/LTR/VERR/VERW/-/- group. System insns

 * 0f 01 - SGDT/SIDT/LGDT/LIDT/SMSW/-/LMSW/INVLPG group.

 *	Also encodes tons of other system insns if mod=11.

 *	Some are in fact non-system: xend, xtest, rdtscp, maybe more

 * 0f 05 - syscall

 * 0f 06 - clts (CPL0 insn)

 * 0f 07 - sysret

 * 0f 08 - invd (CPL0 insn)

 * 0f 09 - wbinvd (CPL0 insn)

 * 0f 0b - ud2

 * 0f 30 - wrmsr (CPL0 insn) (then why rdmsr is allowed, it's also CPL0 insn?)

 * 0f 34 - sysenter

 * 0f 35 - sysexit

 * 0f 37 - getsec

 * 0f 78 - vmread (Intel VMX. CPL0 insn)

 * 0f 79 - vmwrite (Intel VMX. CPL0 insn)

 *	Note: with prefixes, these two opcodes are

 *	extrq/insertq/AVX512 convert vector ops.

 * 0f ae - group15: [f]xsave,[f]xrstor,[v]{ld,st}mxcsr,clflush[opt],

 *	{rd,wr}{fs,gs}base,{s,l,m}fence.

 *	Why? They are all user-executable.

 */

static volatile u32 good_2byte_insns[256 / 32] = {

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

	/*      ----------------------------------------------         */

	W(0x00, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1) | /* 00 */

	W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* 10 */

	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 20 */

	W(0x30, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */

	W(0x00, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1) | /* 00 */

	W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 10 */

	W(0x20, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 20 */

	W(0x30, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* 30 */

	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */

	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 50 */

	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 60 */

	W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1) , /* 70 */

	W(0x70, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* 70 */

	W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */

	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 90 */

	W(0xa0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1) | /* a0 */

	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1) , /* b0 */

	W(0xa0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1) | /* a0 */

	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* b0 */

	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* c0 */

	W(0xd0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */

	W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* e0 */

	W(0xf0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)   /* f0 */

	W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1)   /* f0 */

	/*      ----------------------------------------------         */

	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f         */

};

#undef W



/*

 * opcodes we'll probably never support:

 *

 *  6c-6d, e4-e5, ec-ed - in

 *  6e-6f, e6-e7, ee-ef - out

 *  cc, cd - int3, int

 *  cf - iret

 *  d6 - illegal instruction

 *  f1 - int1/icebp

 *  f4 - hlt

 *  fa, fb - cli, sti

 *  0f - lar, lsl, syscall, clts, sysret, sysenter, sysexit, invd, wbinvd, ud2

 *

 * invalid opcodes in 64-bit mode:

 *

 *  06, 0e, 16, 1e, 27, 2f, 37, 3f, 60-62, 82, c4-c5, d4-d5

 *  63 - we support this opcode in x86_64 but not in i386.

 *

 * opcodes we may need to refine support for:

 *

 *  0f - 2-byte instructions: For many of these instructions, the validity